docs: def get_sns_topic_arn(topic_name, account, region):
      """Get SNS topic ARN.
  
      Args:
          topic_name (str): Name of the topic to lookup.
          account (str): Environment, e.g. dev
          region (str): Region name, e.g. us-east-1
  
      Returns:
          str: ARN for requested topic name
  
      """
      if topic_name.count(':') == 5 and topic_name.startswith('arn:aws:sns:'):
          return topic_name
      session = boto3.Session(profile_name=account, region_name=region)
      sns_client = session.client('sns')
  
      topics = sns_client.list_topics()['Topics']
  
      matched_topic = None
      for topic in topics:
          topic_arn = topic['TopicArn']
          if topic_name == topic_arn.split(':')[-1]:
              matched_topic = topic_arn
              break
      else:
          LOG.critical("No topic with name %s found.", topic_name)
          raise SNSTopicNotFound('No topic with name {0} found'.format(topic_name))
      return matched_topic